摘要:

Tetramethylcyclobutadieneiron tricarbonyl has been obtained in 25–37% yield from the reaction of triiron dodecacarbonyl with either 3,4-dichlorotetramethylcyclobutene or tetramethylcyclobutadienenickel chloride dimer. The latter reaction also gave small amounts of another complex, Me8C8NiFe(CO)3. The reaction of [Me4C4NiCl2]2with iron pentacarbonyl gave Me4C4Fe(CO)3together with two other complexes. The structures of these new complexes are discussed in the light of their nuclear magnetic resonance, mass, and infrared spectra.

ISSN:0008-4042    

DOI:10.1139/v67-326

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

The ligand-transfer reaction of tetramethylcyclobutadienenickel chloride dimer with dicobalt octacarbonyl gave tetramethylcyclobutadienedicobalt hexacarbonyl [Me4C4Co(CO)2Co(CO)4] and nickel tetracarbonyl. Triphenylphosphine replaced one carbonyl in Me4C4Co(CO)2·Co(CO)4to give Me4C4Co(CO)2·Co(CO)3PPh3. Both Me4C4Co(CO)2·Co(CO)4and Me4C4Co(CO)2·Co(CO)3PPh3underwent cleavage with iodine at low temperatures to give tetramethylcyclobutadienecobalt dicarbonyl iodide (Me4C4Co(CO)2I); this was also obtained in quantitative yield from [Me4C4NiI2]2and Co2(CO)8. One carbonyl in Me4C4Co(CO)2I was replaced on reaction with triphenylphosphine, giving Me4C4Co(CO)(PPh3)I. Me4C4Co(Co)2I reacted with both sodium cyclopentadienide and [C5H5Fe(CO)2]2to give (π-cyclopentadienyl)-(π-tetramethylcyclobutadiene) cobalt.

ISSN:0008-4042    

DOI:10.1139/v67-327

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

The secondary α-deuterium isotope effect in iodide-131 exchange of methyl-d3iodide iskH/kD = 1.05 ± 0.01 in methanol and 1.10 ± 0.04 in water at 20°. A correlation of secondary α-deuterium and13C effects, in bimolecular nucleophilic substitution reactions, with the difference ofEvalues between nucleophile and leaving group is presented.

ISSN:0008-4042    

DOI:10.1139/v67-328

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

Ultraviolet spectral studies of hydrogen bonding between phenol and N,N-dimethylacetamide (DMA) in several media are reported. The equilibrium constant for the formation of the phenol–DMA complex is strongly solvent dependent, varying from 295 1/mole in cyclohexane to 130 in CCl4and 16 in CHCl3, all at 28°. The greatly reduced value in CHCl3indicates that the measured equilibrium constant is only an apparent one which does not take into account the decrease in free DMA concentration resulting from hydrogen-bonded complex formation with the solvent acting as hydrogen donor. In CCl4/CHCl3mixed solvent, in the range of [chloroform] = 0 to 1.227 M, the measured equilibrium constant,K′, varies linearly withK′ [chloroform]. The slope of the line corresponds to the equilibrium constant for the formation of the hydrogen-bonded complex between CHCl3and DMA in CCl4. The value, 0.9 1/mole, agrees with that obtained from a proton magnetic resonance method. The agreement is particularly noteworthy when we consider that the concentrations of phenol used in the proton magnetic resonance and ultraviolet spectral methods differ by a factor of 200, which leads definitely to the conclusion that the hydrogen-bonded CHCl3–DMA complex formed is 1:1. In cyclohexane/CHCl3mixed solvent, similar results are obtained.

ISSN:0008-4042    

DOI:10.1139/v67-329

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

The cathodic passivation of β-PbO2electrodes in electrolytes based on perchlorate ion has been studied as a function of current density and electrolyte composition.Before passivation the electrode remains free of films based on Pb(II).Passivation results are correlated in the form of a modified diffusion equation incorporating two parameterskpandi1.

ISSN:0008-4042    

DOI:10.1139/v67-330

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

The results of short time galvanostatic polarization experiments are described in which the maximum potential excursion is limited to ± 10 mV about the equilibrium potential.Exchange currents have been evaluated both geometrically and iteratively. The charge transfer reactionis slow. The dependence of the exchange current on the concentration of Pb(II) is consistent with a charge transfer coefficient of 0.2 in agreement with the arithmetical analysis of current–potential data.There is evidence for an adsorbed layer of hydrogen ion at the electrode.

ISSN:0008-4042    

DOI:10.1139/v67-331

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

By using small doses and very low dose rates, it is shown that in the γ-irradiation of water ~ 8 × 10−5Mnitrous oxide completely scavenges eaq−in the absence of other additives and gives a yield G(eaq−) = 2.45 ± 0.1. When used at concentrations of ~ 15 mM, N2O scavenges a second species having a yieldG = 0.65 ± 0.1, which can probably be attributed to a hydrated hydrogen atom species resulting from the reaction of eaq–with H3O+within the spur. Previous studies on the competition between N2O and Haq+for eaq−have been conducted at concentrations of N2O much too high for simple competition to be valid, which probably accounts for the erratic results obtained. This paper reports on the competition studied at ~ 10−4 M. The results cannot be interpreted either in terms of a simple competition or by one, or both, of the immediate products reacting with either of the additives. The data can only be rationalized by assuming that in acid solution N2O is converted to a species, tentatively suggested to be H2N2O2, which reacts with eaq−5 times more slowly than does N2Oaqat pH 7.

ISSN:0008-4042    

DOI:10.1139/v67-332

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

The Π-electron networks in boron–nitrogen chains and rings have been treated by l.c.a.o.–m.o. techniques. The results for B—N chains predict a very weak alternation of bond order, smaller charges on the terminal atoms than on the internal atoms, and very little conjugation across B—B and N—N linkages. The calculations for the B—N rings predict an absence of a "4n + 2" pi-electron rule for aromaticity and a predominance of exocyclic over endocyclic Π bonding in the substituted rings. These results are compared with the properties of known B—N chains and rings and are contrasted with l.c.a.o.–m.o. calculations for the analogous carbon–carbon systems.

ISSN:0008-4042    

DOI:10.1139/v67-333

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

The temperature dependence of the rate of hydrolysis of α-bromoisobutyrate ion in water was determined over a temperature range 9–37 °C. From these data corresponding values of ΔH≠, ΔS≠, and ΔCP≠have been derived. The implication of these terms, together with corresponding data for hydrolysis in D2O and for the secondary deuterium isotope effect from the hydrolysis of (CD3)2CBrCOO−, provide a basis for reexamining the detailed mechanism with particular reference to accompanying solvent reorganization.

ISSN:0008-4042    

DOI:10.1139/v67-334

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

Velocity of sound was measured to an accuracy of 0.1% in liquid argon, krypton, and xenon under saturated vapor conditions by a resonance ultrasonic technique. Measurements in argon and krypton were from their normal boiling points to close to their critical points, while those in xenon were from its triple point to close to its critical point. Adiabatic compressibilities of these liquids were calculated in the temperature regions for which density data were available.Analysis of the results indicates that such velocity data can provide a precise test of the principle of corresponding states, in its classical and quantum forms. The corresponding states principle holds quite well in the above liquids when subjected to this test.The velocity data in all cases agree more closely with tunnel model calculations than with cell model calculations.

ISSN:0008-4042    

DOI:10.1139/v67-335

出版商:NRC Research Press    

年代:1967

数据来源: NRC